Discovery of Electrons (Cathode Rays)

Source:  Discovery of Electrons (Cathode Rays)    Tag:  cathode ray discharge tube
Discovery of Electrons (Cathode Rays)


  • A gas discharge tube is fitted with metal electrodes known as cathode and anode.
  • This glass tube is filled with Gas.The Electrodes are connected with high voltage battery.
  • The exact voltage required depend upon the length of glass tube and pressure of gas inside tube.
  • A vacuum pump is attached to glass side from a side in order to decrease pressure of gas inside tube.
  • It is observed that current does not flow through gas at ordinary pressure.
  • When pressure of Gas is reduced to 0.01 torr and high current of 5000-10000 voltages is applied,electric discharge takes place through the gas.
  • Some rays are produced which creates greenish fluorescene on the walls of glass tube.
  • As these rays were produced from Cathode they were named as "cathode rays".
  • The colour of glow or fluorescene produced on the walls of glass depends upon the composition of glass.
electrons,cathoderays